Extension-table



UNITED STATES Param. .OFFICE-N GEORGE PRATT, OF BOSTON,l MASSACHUSETTS.

EXTENSION-TABLE.

Specification of Letters Patent No.V 5,905, dated November '7, 1848.

To all whom t may concern.'

Be it known that I, GEORGE PRATT, of Boston, in the county of Suffolk and State of Massachusetts, a subject of Great Britain, but having resided the year past in the United States of America and made oath of intent-ion to become a citizen of the same, have invented a new and useful Improvement in Extension-Tables; and I do hereby declare that the same is fully described and l represented in the following specification 'from a common center.

and accompanying drawings, letters, figures, and references thereof.

Of said drawings, Figure l exhibits a top .view of one of my improved tables, ex-

tended, and without any of its movable lill-r ing leaves or top boards. Fig. 2 is an underside or bottom view of the same. Fig. 8 is a side elevation of said table, Fig. I isla top legs C, D, or E, F, in the usual manner.y

The one part A from which the other B, is to be made to depart, and advance toward, as occasion may require, in order to extend or diminish the length of the table, has twoy parallel bars G, H, aiiixed to its under side as seen in Figs. l and 2. In connection with said parallel bars, I make use of four or-any'V other suitable number of sets of two parallel slide bars, I, K, L, M, N, O, P Q, the latter set of which viz, P Q,'i's fixed to the under side of the other half o'r part B. The bars I K, are arranged between the bars G, `H,

and connected respectively to them by a` dovetailed tongue and gr`oove,the tongue befing made upon oneof the two bars in contact and the groove in the other, in order that the two I,KK, may be' made to slide freely between, the two G, H in the manner, in which such slides usually operate. Or instead of such an arrangement of the tongues and grooves thatl exhibited inV Fig. 4,` and hereinafter described may be employed. 4

Fig. 7, denotes a vertical and transverse section of the upper part of the table,lthe

sanie being taken in lineof the axis of the pinion shaft R. .In said figure the aforementioned tongues andvgrooves'are seen at a, a. The bars K, M, M, O, O Q, I L, LN, N P, are similarly adapted to slide the one against the other, the grooves and tongues of them serving to preserve their horizontal positions.V v l i y The pinion shaft- R., before mentionedv turns in boxes or bearings b, b, applied to arranged in the position as seenI inthe draw*- ings, and has four toothed gears or'pinions c Z e f, afiixed upon it, each'of which should be in its width about double that of each toothed rack in which it is .made to operate. To the'under'side of each of the slide bars UI, K, L M', N O, P Q, a long toothed rack is applied and fixed, as seen at i, lc, Z m, n o, p g, in Fig. 2, while the pinion c, isp'laced f the under side of the fxed'bars G, H. It is f' so as to operate in the racks, f, my, the pin-v ion al, is disposed so as to operatein the racks o, g, vwhen brought into engagement.y

So with the .other pinions e f, they are ar;V

ranged so las atthe sametimes to operate in the corresponding Vopposite racks By :inspection ofthe drawings it will read-4 ily be seen that by revolving the pinion shaft, by applying the handv tothe crank s, thereof, the two slide bars may be moved inward or in consequencer of the action of the two pin-i ions o and f upon their respective racks lc, i.,

To the upper side and near one end of each vr'ofthe slide barsI, K, L M, N, O, a dog- .toward the board A, the same taking place' ging lever T,'is affixed as seen in Figs. l, Said dogging lever turns horizontallyl on a fulc'rum orvscrew g, and is'shaped, that is to say ithas three projecti ms h, 7', s, as in the' drawings.- Each slide bar L N O, 1P'

has a notch ,made init and near one endt of it,' and of a size sufficient to admit or re v ceive the projection vlz., of the dogging lever T of the next adjacent slide bar. Y f Each of the bars G, H, I, K, LM,JN` O,

has a notch u made in it of asize and forni v sufficientto'receive the projection the lever of the adjacent bar the positionsnof each of said notches or spaces u', beingfseen in the drawing. The inner corner' of the outer end of. each of thebars, G, H,"I`, K,

L M, is rounded olf as seen at e in Fig; l," the object of the same being when the pro# jection s, of thedogging lever T of the slide bar that slides against the bar ywhose corner -is so rounded, is brought and movedin con:` 5f

the pinion or gear of the pinionrshaft, and which has just become engaged with the rack of the slide bar to be drawn in, to' so operate within the said rack as to propel or force backward the slide bar of the said rack.

From the above it will be seen thatduring the act of closing the table, each set I. K. L.

M. N O. P Q. of two bars, is successively unlatched from the one which slides on the outside of it, and so as to enable its geared pinions to operate in its racks, and draw the others between it and the part B. of the table together with said part toward the part A.

In expanding the table, the pinion shaft is rotated in the opposite direction. The slides P and Q. are first forced outward by the action of their pinions, in their racks. As soon as they-have advanced so far as to carry the rear ends of the dovetailed tongues of the slidesvN. O. in contact with the .front ends of the dovetailed grooves of the slides P. Q. the said slides P. Q. will commence to draw after them the adjacent slides N. O. and will continue to so draw them, until the dogging levers of said slides N O. are moved on their fulcra in such manner as to cause their projections it. to enter the notches in the slides P Q. and by so doing latch said slides to the slides N. O. The said movement of each of the said levers will be caused by the action of its projection r. .and the notch in which .it may be. Theside of the said notch acting against the side of the projec-A tion in contact with it, causes the lever to turn on its 'fulcrunr As soon as this hasbeen accomplished the racks of the bars P. Q. will have passed beyond or out of gear with the pinions which previously moved them; and the said pinions will operate or engage with the racks of the bars N. O. and advance them and the bars P.` Q.. Each succeeding set of bars will thus be moved forwardand latched to the one outside of it, until the table is fully extended.

Fig. 12. represents the dogging lever T.

and bars K. O. M.'on an enlarged scale. On the pinion shaft I place a ratchet wheel U,` and I afx to the side of the bar H. or a piece of wood V. secured thereto, a retaining lever pawl or click W. the same being to prevent the pinion shaft from turning around, so as to allow of any accidental or undesirable extension of the table. When the table is being extended said click or pawl is to be raised out of gear with the teeth of the ratchet wheel.

The crank for turning; the pinion shaft has a tubular socketw. which is placed and slides upon the pinion shaft. The end of said pinion shaft which is within the tubular socket, has a key or small projections m. m. m. ai. made upon it as seen in Fig. 8.which denotes an end view of said part of said shaft. The inner end of the tubular socket' is made as seen in Fig. 9. orl so as to receive said projections in 'such manner as to clutch the crank, to the shaft, when the former is drawn outward to its full extent. When unclutched from the shaft the crank may be turned around on the shaft, and forced inward and turned upward into a recess y, made in the side board 2 of the table. It

'thus may-be moved out of sight, `when not in use, and when it is required to extend or contract the table, the said crank may be drawn outward into a convenient .position to enable a person to take hold of its handle and rotate the shaft. Fig. 10, exhibits a vertical section of the crank and tubular socket, and part of the .pinion shaft. is raised into its socket it may be retained there the necessary time by a spring or any other suitable contrivanceproperly adapted to it. So in order to keep the pawl or click out of gear with the ratchet Wheel, a spring or any other proper equivalent may be used.

Fig. 11, represents a horizontal section of two of the slide bars L and N, Fig. l, the said section being taken through the dovetailed tongues and grooves of each. a, b, in the said figure denote the short tongues, the former being made to project from the Then vthe crank bar L, and to enter the dovetailed groove c of the bar N, while the latter (b) is made 'to extend from the bar N, and enter the groove ci, of the other bar.

'A table in which the .two ends or parts A, B, are made to depart from a central or middle frame C, C, is exhibited in Figs. 4f, 5 and 6. The said central frame is composed of the curved sides D, D, and six parallel bars E, E, &c., arranged between said curved pieces, the whole being kept in place by two bottom bars G, G, extending transversely across and underneath them. The several parallel bars are disposed (as seen in the drawings) so as to receive four sets of slide bars between them. One of said sets is seen at H, H, as adapted to `and made to slide between, another set composed of four bars I, I, I, I, which are disposed between the four middle bars E, E, E, E, as seen'in the drawings.

Another of said sets of slide bars is seen at K, K, while the fourth set is seen at L, L, L, L. The former operate between the latter, and the latter between the four outer bars E, E, the same being arranged as seen vin Fig. 4. The dogging levers with their respective notches and projections are adapted to the said systems of slides and fixed I the ratchet wheel of said vertical shaft.

and ixed parallel bars, are'united by dovetailed or other proper tenons, and grooves,

substantially like the others yherein before speciied. In this latter table two pinion shafts M, N, are necessary to its operation. They are arranged and have their pinions and racks disposed as seen in the drawings. On the main driving pinion shaft, I place a toothed or chain wheel O. I also aflix another and similar chain wheel 13,011 the other shaft, and I connect them by a crossed endless chain R, made to extend around them. In this table the main pinion shaft is worked by a crank S, which is affixed to a small vertical shaft T geared to the main pinion shaft by a set of two bevel gears, one of which is affixed upon each shaft. T denotes U, is the spring pawl of said ratchet.

Having thus described my improvement I wish it to be understood that I do not confine it to the precise forms or arrangements.

of parallel bars, (G, I-I), K), (L, M), (N, O), (P, Q) the machinery for extending and contracting the slide bars thereof or moving them outwardand inward and the latching and unlatching contrivances, as applied and operating substantially in manner as above described.

2. I also claim the said latching and un latching contrivances as constructed and applied to their slide bars, and operating (when they are moved, by mechanism substantially as set forth) to connect or disconnect them, in manner essentially, as herein before explained.

3. I also claim the above described -man ner of adapting the crank of the pinion shaft R, to said shaft, so that said crank may be moved or drawn outward, and forced inward and turned upward into a socket, and be made to clutch or engage with, and be disengaged from the shaft, as occasion may. require.

In testimony whereof I have hereto set my i signature.

GEORGE PRATT.

Witnesses:

R. I-I. EDDY, D. H. Ti'LLsoN. 

